Since a national introduction in 1965, Americans have come to increasingly depend on universal access to emergency services via the digits 9-1-1. The digits 911 have become synonymous with emergency telephone calls, and it has been estimated that 200 million 911 calls are made each year in the United States. Universal use of these three digits for access to emergency services gives callers ready access to state and local emergency responders regardless of the jurisdiction from which the call is being made. The system has become an effective and reliable conduit for directing life saving efforts of first responders to where they are needed.
911 service generally falls into one of two categories, basic 911 and enhanced 911 (E911). Basic 911 service forwards a 911 call from a telephone service provider's switch to a geographically appropriate emergency call center. The call is merely forwarded to this center and no further information about the call is provided to the call center. The caller's identity and location are disclosed to an answering operator through discussions with the caller.
E911 service instead routes 911 calls using a selective router. The selective router can route a call based on the calling number. The selective router can query a selective router database (SRDB) using the calling number (referred to in 911 terminology as automatic numbering information or ANI) to determine the appropriate public service answering point (PSAP) for handling the call. The call and the ANI are then forwarded to the PSAP which, in turn, queries a location database using the ANI. The location data (referred to as automatic location information or ALI) associated with the ANI is then provided to the PSAP. The ALI returned is a physical address; the integrity of which has been verified by comparison with a separate database known as a Master Street Address Guide (MSAG). E911 calls are routed over a dedicated network which is interconnected with, but separate from, the public switched telephone network (PSTN). The selective router, trunk lines connecting the selective router and the PSAP, the ALI database, the SRDB, trunk lines between the ALI database and the PSAP, and the MSAG together comprise the dedicated wireline E911 network.
While first introduced on the wireline networks of the day, access to emergency services via dialing 911 on modern mobile devices has posed challenges to the operation of the 911 emergency services network. Wireline access is commonly provided by a local exchange carrier, which provides service to a fixed business or residential location. A telephone number of an account can therefore be easily and reliably associated with a corresponding location address in system databases, so that 911 calls received from the number can be routed to an emergency call center best situated to deal with any emergency that exists at that address.
The location of mobile and nomadic devices, however, is not so reliably determined. These devices retain their telephone numbers as they are moved from place to place. Obtaining the required location information for the routing of such calls requires a wholly different, or at least modified, solution. Due to the public's reliance on and expectation of the availability of emergency help via dialing 911 on a telephony device, the Federal Communications Commission (FCC) has taken steps to ensure reliable 911 service continues to be available via these newer technologies.
Mobile telephony devices such as handheld cellular telephones communicate through a network of geographically distributed base stations. At any given time, an active cellular telephone is communicating primarily through one base station. Knowledge of the location of the base station with which the handset is communicating can provide a rough estimate of the location of the handset. The coverage area of a base station, however, can span many square miles. Although a handset communicates primarily with one base station, transmissions from other nearby base stations can be detected by the handset. Transmissions from the handset can be picked up at other base stations as well. By measuring the difference between the times of arrival of handset transmitted signals at several base stations (with known locations), the position of the handset can be determined with far more precision. In addition, handsets which include global positioning sensors can provide location information obtained using positioning satellites orbiting the earth.
The FCC has directed mobile communication providers to make such measurements of device location and provide accurate device location to call routing services for 911 calls. This helps to ensure that emergency calls placed via these mobile terminals are routed to the appropriate call center regardless of the location of the device. Receiving PSAPs are given ANI and ALI for these calls.
More recently, the emergence of Voice over Internet Protocol (VoIP) services has presented yet another challenge to the proper routing of 911 calls. VoIP telephony services transmit and receive voice data in packets having a format appropriate for transmission over the Internet. Instead of a traditional PSTN line, voice signals are sent over a broadband Internet connection and routed over the Internet. Through interconnections with the PSTN, VoIP calls can be sent to and received from the PSTN.
While a VoIP account generally has a static telephone number, the IP address of the broadband Internet connection over which the account is used can be dynamic. Furthermore, even if a static IP is utilized, there is no database which reliably maps IP addresses to physical addresses (although as discussed below an estimate of the location of the physical location where the IP address is being used can be made). In addition, the VoIP equipment can be moved from one location to another so the equipment and the account can be used over more than just a single broadband Internet connection.
Upon first offering telephony services, VoIP providers did not have facilities in place for providing location specific information to the 911 emergency network. VoIP users expecting normal 911 access were, in some cases, routed to emergency call centers several hundreds of miles (or more) away from the caller's physical location. Incidents such as these prompted the FCC to issue a number of requirements applicable to the provision of VoIP services and the availability of reliable 911 access via these services. These requirements can be found in “First Report and Order and Notice of Proposed Rule Making FCC 05-0116” the entirety of which is herein incorporated by reference.
The FCC order requires all interconnected VoIP providers (those who connect calls to the PSTN) to send 911 calls, a call back number (ANI), and a registered location for each call to the public service answering point (PSAP), to a designated statewide default answering point, or to an appropriate local emergency authority that serves the caller's registered location. These calls are required to be routed using ANI and to be routed over the dedicated wireline E911 network.
According to the FCC order, to obtain the necessary information to fulfill the registered location requirement, VoIP providers must obtain service location information from their customers, prior to the installation of service. If the service can be moved from one location to another, the VoIP providers must offer a method for the customers to update the location information. At least one method of updating this information must include the use of the customer premises equipment (CPE) of the VoIP installation. Providers cannot allow customers to opt out of E911 service. The National Emergency Number Association (NENA) has published a proposed architecture for service providers to adopt for implementing the FCC order. This document is entitled “Interim VoIP Architecture for Enhanced 9-1-1 Services (i2)” and can be found at http://www.nena.org/media/files/NENA—08-001_V1—12-06-05.pdf This document is incorporated by reference herein in its entirety.
Delays in processing location information can occur after new VoIP installations. For example, where VoIP equipment is purchased at a point of sale location, the purchaser (VoIP customer) can provide an address for the location where the VoIP will be used. The location can be validated at the point of sale to determine if it is an actual address. This validation, however, does not fully validate the address as MSAG compliant such that it can be used in the E911 system. An MSAG validation can take up to 48 hours and can fail. In that case the location information supplied by the customer cannot be used by the E911 system to enable the selective router to send the call to the appropriate PSAP. It is also possible that the address information could be corrupted (through a failed update for example) or obsolete due to the VoIP equipment being moved to a location which differs from the location on record with the VoIP provider.
Systems and methods are therefore needed for providing a default treatment in cases where location information supplied by the customer is unavailable or obsolete. Such systems and methods can route calls to emergency call centers which are capable of dispatching responders to the source location of the call (as closely as that can be determined from the available information) or to a center capable of quickly communicating with or capable of forwarding the call to the center.